package com.musclehack.musclehack.images;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Collections;
import java.util.Map;
import java.util.WeakHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import com.musclehack.musclehack.R;

import android.os.Handler;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;
import android.widget.ImageView;

public class ImageLoader {
	
	MemoryCache memoryCache=new MemoryCache();
	FileCache fileCache;
	private Map<ImageView, String> imageViews=Collections.synchronizedMap(new WeakHashMap<ImageView, String>());
	ExecutorService executorService;
	Handler handler=new Handler();//handler to display images in UI thread
	
	public ImageLoader(Context context){
		Log.d("ImageLoader", "public ImageLoader(Context context) called");
		fileCache=new FileCache(context);
		executorService=Executors.newFixedThreadPool(5);
		Log.d("ImageLoader", "public ImageLoader(Context context) end");
	}

	final int stub_id=R.drawable.rss_empty;
	public void DisplayImage(String url, ImageView imageView){
		Log.d("ImageLoader", "public void DisplayImage(String url, ImageView imageView) called");
		imageViews.put(imageView, url);
		Bitmap bitmap=memoryCache.get(url);
		if(bitmap!=null)
			imageView.setImageBitmap(bitmap);
		else
		{
			queuePhoto(url, imageView);
			imageView.setImageResource(stub_id);
		}
		Log.d("ImageLoader", "public void DisplayImage(String url, ImageView imageView) end");
	}
		
	private void queuePhoto(String url, ImageView imageView){
		PhotoToLoad p=new PhotoToLoad(url, imageView);
		executorService.submit(new PhotosLoader(p));
	}
	
	private Bitmap getBitmap(String url){
		Log.d("ImageLoader", "private Bitmap getBitmap(String url) called");
		File f=fileCache.getFile(url);
		
		//from SD cache
		Bitmap b = decodeFile(f);
		if(b!=null){
			Log.d("ImageLoader", "private Bitmap getBitmap(String url) end 1");
			return b;
		}
		
		//from web
		try {
			Bitmap bitmap=null;
			URL imageUrl = new URL(url);
			HttpURLConnection conn = (HttpURLConnection)imageUrl.openConnection();
			conn.setConnectTimeout(30000);
			conn.setReadTimeout(30000);
			conn.setInstanceFollowRedirects(true);
			InputStream is=conn.getInputStream();
			OutputStream os = new FileOutputStream(f);
			Utils.CopyStream(is, os);
			os.close();
			conn.disconnect();
			bitmap = decodeFile(f);
			Log.d("ImageLoader", "private Bitmap getBitmap(String url) end 2");
			return bitmap;
		} catch (Throwable ex){
			ex.printStackTrace();
			if(ex instanceof OutOfMemoryError){
				memoryCache.clear();
			}
			Log.d("ImageLoader", "private Bitmap getBitmap(String url) end 3");
			return null;
		}
	}

	//decodes image and scales it to reduce memory consumption
	private Bitmap decodeFile(File f){
		Log.d("ImageLoader", "private Bitmap decodeFile(File f) called");
		try {
			//decode image size
			BitmapFactory.Options o = new BitmapFactory.Options();
			o.inJustDecodeBounds = true;
			FileInputStream stream1=new FileInputStream(f);
			BitmapFactory.decodeStream(stream1,null,o);
			stream1.close();
			
			//Find the correct scale value. It should be the power of 2.
			final int REQUIRED_SIZE=70;
			int width_tmp=o.outWidth, height_tmp=o.outHeight;
			int scale=1;
			while(true){
				if(width_tmp/2<REQUIRED_SIZE || height_tmp/2<REQUIRED_SIZE)
					break;
				width_tmp/=2;
				height_tmp/=2;
				scale*=2;
			}
			
			//decode with inSampleSize
			BitmapFactory.Options o2 = new BitmapFactory.Options();
			o2.inSampleSize=scale;
			FileInputStream stream2=new FileInputStream(f);
			Bitmap bitmap=BitmapFactory.decodeStream(stream2, null, o2);
			stream2.close();
			Log.d("ImageLoader", "private Bitmap decodeFile(File f) end 1");
			return bitmap;
		} catch (FileNotFoundException e) {
		} 
		catch (IOException e) {
			e.printStackTrace();
		}
		Log.d("ImageLoader", "private Bitmap decodeFile(File f) end 2");
		return null;
	}
	
	//Task for the queue
	private class PhotoToLoad
	{
		public String url;
		public ImageView imageView;
		public PhotoToLoad(String u, ImageView i){
			url=u; 
			imageView=i;
		}
	}
	
	class PhotosLoader implements Runnable {
		PhotoToLoad photoToLoad;
		PhotosLoader(PhotoToLoad photoToLoad){
			this.photoToLoad=photoToLoad;
		}
		
		@Override
		public void run() {
			try{
				if(imageViewReused(photoToLoad))
					return;
				Bitmap bmp=getBitmap(photoToLoad.url);
				memoryCache.put(photoToLoad.url, bmp);
				if(imageViewReused(photoToLoad))
					return;
				BitmapDisplayer bd=new BitmapDisplayer(bmp, photoToLoad);
				handler.post(bd);
			}catch(Throwable th){
				th.printStackTrace();
			}
		}
	}
	
	boolean imageViewReused(PhotoToLoad photoToLoad){
		String tag=imageViews.get(photoToLoad.imageView);
		if(tag==null || !tag.equals(photoToLoad.url))
			return true;
		return false;
	}
	
	//Used to display bitmap in the UI thread
	class BitmapDisplayer implements Runnable{
		Bitmap bitmap;
		PhotoToLoad photoToLoad;
		public BitmapDisplayer(Bitmap b, PhotoToLoad p){bitmap=b;photoToLoad=p;}
		public void run(){
			if(imageViewReused(photoToLoad))
				return;
			if(bitmap!=null)
				photoToLoad.imageView.setImageBitmap(bitmap);
			else
				photoToLoad.imageView.setImageResource(stub_id);
		}
	}

	public void clearCache() {
		memoryCache.clear();
		fileCache.clear();
	}

}
